Some types of vehicle systems may allow a driver or passenger to provide input without manipulating buttons or other tactile inputs. More specifically, the vehicle may receive nonverbal communication from an individual using hand gestures. The vehicle includes sensors to detect the movement and position of an individual's hand, and determines the information the individual is attempting to convey based on the movement and position of the hand. However, some challenges may exist in certain situations that can limit the system's ability to interpret some of the information expressed by an individual's hands.
In addition to systems that allow for a driver to provide input based on hand gestures, some vehicles include an eye-tracking system that is capable of tracking the driver's gaze direction. The driver's gaze direction may be used to determine the driver's level of awareness as he or she is operating the vehicle. The driver normally directs his or her attention towards the environment located in front of the vehicle. Therefore, drivers typically direct their gaze away from the front of the road for only a few moments at a time while operating the vehicle. For example, a driver may turn his or her head to the side and look out of one of the side windows of a vehicle, but only for a few seconds. Accordingly, eye-tracking systems are limited in their ability to determine commands based on the gaze direction of the driver.